MPGs?

groundshock

Original poster
Member
Dec 4, 2011
248
Seriously. What are you guys putting down for mileage? I've got the smaller 18 gallon tank and I cannot get 300 miles out of a tank no matter how hard I try. This thing has NEVER gotten over 15mpg, ever.

I've got a homemade CAI, and a PCM4Less tune if that matters, but it still has neeeever gotten anything close to acceptable mileage. I'm always on top of my tire pressures, all fluids are changed on a regular basis.

Any input?
 

Sparky

Member
Dec 4, 2011
12,927
What kind of driving do you do? Terrain?

I average 17-19 but I do mostly highway. I'm guessing maybe a 80/20 split. Something like that. Terrain around here is fairly flat for the most part. My truck is bone stock on pretty much everything.

I'm usually filling up between 250-300 miles.
 

groundshock

Original poster
Member
Dec 4, 2011
248
Flat everything. Lake shore. City driving, hardly ever see 55.

I'm just blown away how this thing sucks like an old drunk. I love everything about this thing, except the mileage. It's the first vehicle out of (no kidding) the probably 30 I've had that I don't ever want to sell, but the mileage is just crap.

Thats kinda why I started the 5.3 thread, I figure if it's going to suck fuel like this then at least I should be gifted with some power fer chrissakes. Idk. I figured 18-19 would have been expected at least but ugh.
 

Blckshdw

Moderator
Nov 20, 2011
10,654
Tampa Bay Area, FL
I usually am right around 15.6-15.9 when I fill up every other week from mostly city driving (commuting). I plan to get tuned this summer, hoping to see a bit of a bump in the city numbers, but I'm not expecting too much there.

When I do highway cruising, if I keep it just under 60 (about 1500-1700 RPMs), my scangauge tells me that's the sweet spot, and I can see 21 MPG and sometimes up to 23 depending on outside temp, if I can cruise behind a semi, and get a tail wind. :cool: When I take it up to 65, MPGs drop to around 18 (where the LWBs are rated for highway), up to 75 and the MPGs drop down to around 16. So there's always a bit of a balancing act going on.
 

newfie6719

Member
Sep 27, 2012
50
groundshock said:
Seriously. What are you guys putting down for mileage? I've got the smaller 18 gallon tank and I cannot get 300 miles out of a tank no matter how hard I try. This thing has NEVER gotten over 15mpg, ever.

I've got a homemade CAI, and a PCM4Less tune if that matters, but it still has neeeever gotten anything close to acceptable mileage. I'm always on top of my tire pressures, all fluids are changed on a regular basis.

Any input?

i would love to see 15 mpg, i mine be getting 11 mpg max but it's winter and it's really hilly here. and all short runs no highway at all.
 

Matt

Member
Dec 2, 2011
4,009
Aside from city only driving, do you have a 4.10 rear? That would explain a lot. I also have the 18gl tank but even in winter I'm getting around 250 miles from a fill, mostly city with some highway every now and then. In summer I get 300+ miles, but I also have a 3.42 rear.
 

htseat2000

Member
Jan 25, 2013
62
groundshock said:
Seriously. What are you guys putting down for mileage? I've got the smaller 18 gallon tank and I cannot get 300 miles out of a tank no matter how hard I try. This thing has NEVER gotten over 15mpg, ever.

I've got a homemade CAI, and a PCM4Less tune if that matters, but it still has neeeever gotten anything close to acceptable mileage. I'm always on top of my tire pressures, all fluids are changed on a regular basis.

Any input?

i have a 2003 enovy ext with the 4.2, 113,000 miles and k&n air filter. around town during the winter i get around 13 to 13.5mpg. now on a weekend trip to my parents house last weekend at 70mph and was 90 percent highway 10 percent city i averaged 19.0 mpg overall. on the way there though traveling 70 i checked it when i pulled in the parents driveway and it was 21.5mpg.
 

Sparky

Member
Dec 4, 2011
12,927
Well, it is a 4600 pound vehicle with the aerodynamics of a brick, so...
 

djthumper

Administrator
Nov 20, 2011
14,950
North Las Vegas
I am lifted and have over-sized tires and get around 250 from a tank. Mixed driving for the commute.
 

Boricua SS

Member
Nov 20, 2011
3,080
Ohio
Not a 4.2, but my SS gets anywhere from 18-19 Highway (fully modded too) and about 14 city... 6.0L w/4.10 gears
 

jeffro312

Member
Oct 4, 2012
442
East Haven,Ct
My absolutely stock rainier i6 got me average 22 mpg for my 800 mile trip to sc
I was very surprised by this

Also was please with the gas prices as I went south.
Ct. 3.95
Sc. 3.32

Should have stocked up some gas cans ha.
 

DFWWIZ

Member
Dec 5, 2011
516
Boricua SS said:
Not a 4.2, but my SS gets anywhere from 18-19 Highway (fully modded too) and about 14 city... 6.0L w/4.10 gears

About like mine...13's city (would be better if I didn't have all that powa and lead foot). Hwy keeping around 70 mph or less its 18-20. If I could cruise on level road all the time at 70 it would be 21 mpg and thats with 3200 stall convertor.
 

tbuckalew14

Member
Nov 20, 2011
380
I don't understand how some of you are getting such great gas mileage. I've never seen above 14...With slightly larger tires i'm at 11-12. I've tried everything to bring it up too...tune, cai, exhaust...I don't drive with a heavy foot either. Oh well. I'll still drive it till it dies.
 

BoldAdventure

Member
Jun 28, 2012
1,634
tbuckalew14 said:
I don't understand how some of you are getting such great gas mileage. I've never seen above 14...With slightly larger tires i'm at 11-12. I've tried everything to bring it up too...tune, cai, exhaust...I don't drive with a heavy foot either. Oh well. I'll still drive it till it dies.

How you drive is a huge factor.

We even lightened our vehicle for an experiment where we practiced a ton of hyper miling and got it up to 20mpg. But it wasn't worth the effort.
 

groundshock

Original poster
Member
Dec 4, 2011
248
Sad that the SS gets markedly better mileage. Guess its proof positive that there's just not enough balls in this thing. :smile:
 

Mesoholics

Member
Apr 2, 2012
77
On our last Storm Chasing trip we averaged 18.9 hand calculated MPGs over the 2 week 9000mi trip. That is mostly highway driving with some balls to the wall "chase" tanks deflating the numbers. Unmodded I6, the onboard computer was saying 19.5MPGs average.
 

blazinlow89

Member
Jan 25, 2012
2,088
I drive about 5 miles each way to work, not highway, but not city and its not rural lol. I have about 5 traffic lights and wait about 10 minutes in line to get on base every morning. Right now I have 1/4 rank left and the trip odometer is at 175 miles. I usually average about 230 before the light kicks on. Hand calculations have me around 13-14 MPG. I have slightly larger AT tires,3.42 gears and no lift yet. I am waiting for summer to see the average as the tires had been replaced right before winter. Before the tires during the summer I would get about 15-16 MPG. My highway mileage has always been great anywhere from 23-25 with an all time best of 26. That's with 4 passengers and fully loaded with a cargo rack on the back.

It does make me wonder though if my cat suffered when my tstat went.
 

million-miles

Member
Jan 10, 2012
189
Once you go bigger on the tires no matter how much bigger the rolling mass will kill MPG.
 

blazinlow89

Member
Jan 25, 2012
2,088
million-miles said:
Once you go bigger on the tires no matter how much bigger the rolling mass will kill MPG.

My only issue is that I know in the past I have always had worse MPG in the winter. Unfortunately I only manually calculate the MPG either when we do a road trip, or I will do it over the course of a couple months after spring starts. My problem is I cannot remember the averages I had during the times. Most of our road trips have been during the summer, of the 2 that we have taken in the winter, one was during a snow storm and 4wd was used often on the interstate as the state of NC apparently does not own any snow plows. The other was the TN which involved lots of up an down. Neither of these would be good to average against say our trips to FL, which has a constant terrain that varies only slightly.

I will wait until April and start doing the hand calcs again.
 

signalnc

Member
Dec 28, 2012
249
blazinlow89 said:
of the 2 that we have taken in the winter, one was during a snow storm and 4wd was used often on the interstate as the state of NC apparently does not own any snow plows.

That's funny. This is my 8th winter in NC. The worst snow removal ever. The sad thing is that they think they are doing a good job. You definately take your life in your hands driving around here in winter precip.
 

blazinlow89

Member
Jan 25, 2012
2,088
signalnc said:
That's funny. This is my 8th winter in NC. The worst snow removal ever. The sad thing is that they think they are doing a good job. You definately take your life in your hands driving around here in winter precip.

It was terrible, it was like as soon as the border went from VA to NC, we had been hit with 6" of un plowed snow on the road. The people driving did not help, swerving across 3 lanes of interstate doing 20 MPH at best. Then passing cars in the ditches, a few jack knifed semis and my favorite was a Durango sitting on its bumpers across a ditch, wheels not even touching the ground. Every time I was able to get a good pace, I would come up about 5 cars that looked like the pace lap prior to a NASCAR race. Flash the highs and then they would all hit the rumble strips, and then back to a good cruising speed.

To top it off, we stop for gas after making it through NC. Reverse gear completely gone, would not budge, no sound. I sat the pass anger seat calculating what a new trans would cost, while my fiancee drove. We stop in GA for food and reverse works, and sti.l have never had another problem (knock on wood).

OK back OT
 

5280_Blazer

Member
Mar 13, 2013
16
I drive 9 miles to, and from work every day, all highway.. I just filled my first tank of gas, as the dealer filled it for me after purchase 3 weeks ago. I drove 306 miles on 19.5 gallons.. 22 gallon tank I believe, but that equates to about 15.6 mpg. I am happy with that because we had a few snow storms this month and I tested the 4wd a few times in the snow. Hopefully summer road trips will get me a little better mpg, but I knew what I was getting into when I bought it!
 

DJones

Member
Jan 21, 2012
701
St. Petersburg, Florida
If wind conditions are right, I can get 25 MPG's on the highway... One time, following an oversized load travelling 55MPH for 40 miles, I got 31 MPG's. I get 19 average driving a city/country combo.
 

gmcman

Member
Dec 12, 2011
4,656
Groundshock....with 3:42 gears, and city driving....uphill, both ways..:biggrin: 15 is a stretch. I have an 02 as well and I just replaced my fan clutch tonight. I'm going to fill up tomorrow but something tells me I will re-coop some MPG's based on my butt-dyno. The fan clutch I replaced was the original, I noticed an immediate difference in driveability and was much snappier.

Who knows, if your fan clutch is stock then it's something to consider. The fan would roar in the morning then settle down, but obviously not enough....very quiet now.

I spoke with someone about getting my injectors cleaned out as well, what he said made sense. The nozzle is positioned in just a way that at optimum spray, the fuel atomizes right behind the intake valve. Take a dirty injector then you get a spray along with very small droplets coming out instead of a perfect atomizing mist, but droplets small enough that they will not atomize fully thus commanding more fuel from the ECM..just a big snowball effect.

He said when he dismantles them after been driven for 100K plus, there is always a varnish and when cleaned there is always an increase in MPG because of the improved atomization. Heck I'm willing to try it, he swears by it so what's to lose......only $25 per injector so it will take awhile to get that money back but with fuel where it is pricewise it's almost a no-brainer....I'll be the test mule.

I have the 4:10 gears and no lift, stock size tires and I am averaging 15-16 MPG, 25 miles to work, first 15 is highway with a few lights, last 10 is stop and go, bumber to bumper...but that was with a bad fan clutch. Ride home is 30 miles and all highway but with about 8-10 red lights. On a road trip I can get about 320 miles comfortably if I keep my foot out of it.
 

seanpooh

Member
Jan 24, 2012
461
DJones said:
If wind conditions are right
We should just put up a mast on the trailvoys to get more mpgs :rotfl:

During the summer (with the 26 gallon tank) I would get about 450 miles on a topped off, gas leaking out tank tank. And that would be 80% highway and country roads delivering pizzas.
Right now I can barely get 325 miles on a full tank with new upstream/downstream 02 sensors, new magnaflow cat and new spark plugs. I have 6 new coil packs to put on to see any change. Stupid winter gas...
 

vipergg

Member
Dec 7, 2011
191
I know on our trip from upstate NY to Florida and back at a consistent 70-72 up and down I95 and I81 I was getting a consistent 22 mpg with a high of 23.6 . I have 3.42 gears and am 2WD though. You certainly notice it in the winter when it gets cold and your trips are short though, it's not the most fuel efficient vehicle and add the wonderful ethanol and winter blended gas and you can kiss your mpg goodbye!! :yes:
 

seanpooh

Member
Jan 24, 2012
461
Just an update, I replaced my transfer case since I suspected it causing a resistance in my driveline. It was true, pulled it out and tried to rotate it, stiff... I turned the shaft where the encoder motor would engage 4x4 and something is not catching/engaging inside like the fork or clutch. I didn't open it since the collision place wanted it as a core assembled.

Well, 3 days now with a used transfer case from the collision place and I'm back to 20-23 mpg on hwy and no more resistance feeling. Also there isn't any downshifting in gears on a slight hill or breezy day. Most likely I'll be back to 400 miles per tank.
 

szieziel

Member
Aug 6, 2012
13
I drive about 90% city and my running average is 12.9mpg actual is about 11city 19hwy (4x4 ext)
in the past 15 months: high of 21 - low of 9, the high one was all highway from Philly to Durham , some of the lows were either extended periods of idling, bad o2 sensor or other maintenance issues

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Decembersend

Member
Dec 3, 2011
316
Body/Suspension Lift on 32" tires, Flowmaster 40 series exhaust, PCM4less tune and I get 13.5 city (w/lead foot) not sure about HWY.
 

Ed H

Member
Oct 18, 2012
167
I drive 7 miles to / from work each day, top posted speed is 45mph, with several stop signs and lights on the way. I am averaging 12.2 mpg over the winter with a very light foot. :no:
 

Pittdawg

Member
Dec 5, 2011
538
You all are tripping me out. I averaged 15 city 21 highway until I modded and then averaged 16 city 22 highway after modding. My engine just went kaput and I'm getting it replaced...I hope I don't get that crap mpgs you all are getting with the replacement.
 

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